1. Field of the Invention
The present invention relates generally to ladders, and particularly to a safety ladder that provides an extension ladder incorporating numerous safety features, which provide greater stability for the ladder and safety for its user.
2. Description of the Related Art
Ladders of various types and configurations have been known for a considerable period of time. Ladders in general may be divided into two different types, i.e., the freestanding stepladder and the plain ladder that requires some other structure for support. The plain ladder includes ladders of unitary structure and extension ladders having one or more sections that slide or telescope relative to one another, the sections extending to provide greater length or retracting for compact storage.
One problem common to all ladders is their inherent instability as a result of their generally relatively narrow base, the elevation of the top of the ladder, and the load (generally a worker) on the ladder, particularly near the top of the ladder. Even in the case of taller extension ladders with the upper end of the ladder resting upon some supporting structure, the relatively narrow base may not provide the required stability when placed upon a soft or uneven surface, as the upper portion of the ladder may slide laterally on its supporting structure (e.g., eaves of a roof, tree branch, elevated railing, etc.). While some ladders have been provided with lateral extensions at their bases to increase their widths, these extensions are generally not retractable and result in considerably greater bulk for the ladder.
Moreover, plain ladders and extension ladders have no defined slope, as do stepladders with their attached bracing and supports. In many instances a plain ladder or extension ladder must be erected at a nearly vertical angle in order to provide the required reach or to position the base upon a suitable surface. This is even more likely with taller extension ladders. The imposition of a relatively large load that is offset outwardly from the plane of the ladder, e.g., a worker climbing the ladder with his or her equipment and supplies, can result in the combined center of gravity of the worker, his or her equipment, and the ladder shifting to a point outside the base of the ladder, i.e., opposite the structure supporting the upper end of the ladder. The result is that the ladder will topple over backwards onto the worker, and possibly damage other structure in the path of the falling ladder.
Another problem common to all ladders is the difficulty in climbing the ladder, particularly when carrying various tools, supplies, and/or equipment. In many instances the worker climbing the ladder is burdened with considerable weight and bulk by the various articles he or she is carrying, with the load further reducing the stability of the worker on the ladder. Even where the ladder is erected with sufficient slope for good forward and rearward stability, the worker climbing the ladder can easily be thrown off balance laterally due to the load he or she is carrying. Yet, the conventional plain ladder or extension ladder provides nothing in the manner of lateral security or support for the worker. He or she is dependent upon whatever grip may be attained from standing on and grasping the relatively narrow rungs of the ladder.
Thus, a safety ladder solving the aforementioned problems is desired.